{"id":2842,"date":"2025-06-01T15:23:43","date_gmt":"2025-06-01T15:23:43","guid":{"rendered":"https:\/\/diznr.com\/?p=2842"},"modified":"2025-06-01T15:23:43","modified_gmt":"2025-06-01T15:23:43","slug":"computer-network-layers-data-link-layer-what-is-a-function-of-the-data-link-layer-and-protocols","status":"publish","type":"post","link":"https:\/\/www.reilsolar.com\/pdf\/computer-network-layers-data-link-layer-what-is-a-function-of-the-data-link-layer-and-protocols\/","title":{"rendered":"Computer network Layers &#8211; Data link layer &#8211; what is a function of the data link layer and protocols"},"content":{"rendered":"<p>Computer network Layers &#8211; Data link layer &#8211; what is a function of the data link layer and protocols<\/p>\n<p>[fvplayer id=&#8221;140&#8243;]<\/p>\n<h3 data-start=\"0\" data-end=\"51\"><strong data-start=\"4\" data-end=\"49\">Computer Network Layers &#8211; Data Link Layer<\/strong><\/h3>\n<p data-start=\"53\" data-end=\"258\">The <strong data-start=\"57\" data-end=\"82\">Data Link Layer (DLL)<\/strong> is the <strong data-start=\"90\" data-end=\"103\">2nd layer<\/strong> in the <strong data-start=\"111\" data-end=\"155\">OSI (Open Systems Interconnection) model<\/strong>. It is responsible for reliable data transfer over a physical link between directly connected devices.<\/p>\n<h3 data-start=\"265\" data-end=\"304\"><strong data-start=\"268\" data-end=\"304\">Functions of the Data Link Layer<\/strong><\/h3>\n<p data-start=\"305\" data-end=\"364\">The Data Link Layer performs the following key functions:<\/p>\n<h3 data-start=\"366\" data-end=\"386\"><strong data-start=\"370\" data-end=\"384\">1. Framing<\/strong><\/h3>\n<ul data-start=\"387\" data-end=\"555\">\n<li data-start=\"387\" data-end=\"491\">Converts the <strong data-start=\"402\" data-end=\"420\">raw bit stream<\/strong> from the <strong data-start=\"430\" data-end=\"448\">Physical Layer<\/strong> into <strong data-start=\"454\" data-end=\"488\">frames (structured data units)<\/strong>.<\/li>\n<li data-start=\"492\" data-end=\"555\">Adds <strong data-start=\"499\" data-end=\"510\">headers<\/strong> and <strong data-start=\"515\" data-end=\"527\">trailers<\/strong> to define frame boundaries.<\/li>\n<\/ul>\n<h3 data-start=\"557\" data-end=\"600\"><strong data-start=\"561\" data-end=\"598\">2. Error Detection and Correction<\/strong><\/h3>\n<ul data-start=\"601\" data-end=\"836\">\n<li data-start=\"601\" data-end=\"722\">Detects errors during data transmission using techniques like <strong data-start=\"665\" data-end=\"698\">Cyclic Redundancy Check (CRC)<\/strong> and <strong data-start=\"703\" data-end=\"719\">Parity Check<\/strong>.<\/li>\n<li data-start=\"723\" data-end=\"836\">Some protocols also provide <strong data-start=\"753\" data-end=\"773\">error correction<\/strong> by requesting retransmission (ARQ &#8211; Automatic Repeat reQuest).<\/li>\n<\/ul>\n<h3 data-start=\"838\" data-end=\"863\"><strong data-start=\"842\" data-end=\"861\">3. Flow Control<\/strong><\/h3>\n<ul data-start=\"864\" data-end=\"1042\">\n<li data-start=\"864\" data-end=\"964\">Manages the <strong data-start=\"878\" data-end=\"907\">rate of data transmission<\/strong> between sender and receiver to <strong data-start=\"939\" data-end=\"961\">prevent congestion<\/strong>.<\/li>\n<li data-start=\"965\" data-end=\"1042\">Uses techniques like <strong data-start=\"988\" data-end=\"1009\">Stop-and-Wait ARQ<\/strong> and <strong data-start=\"1014\" data-end=\"1041\">Sliding Window Protocol<\/strong>.<\/li>\n<\/ul>\n<h3 data-start=\"1044\" data-end=\"1100\"><strong data-start=\"1048\" data-end=\"1098\">4. Access Control (MAC &#8211; Media Access Control)<\/strong><\/h3>\n<ul data-start=\"1101\" data-end=\"1306\">\n<li data-start=\"1101\" data-end=\"1172\">Regulates how multiple devices share the same communication medium.<\/li>\n<li data-start=\"1173\" data-end=\"1230\">Uses <strong data-start=\"1180\" data-end=\"1198\">MAC addressing<\/strong> to uniquely identify devices.<\/li>\n<li data-start=\"1231\" data-end=\"1306\">Implements protocols like <strong data-start=\"1259\" data-end=\"1281\">CSMA\/CD (Ethernet)<\/strong> and <strong data-start=\"1286\" data-end=\"1305\">CSMA\/CA (Wi-Fi)<\/strong>.<\/li>\n<\/ul>\n<h3 data-start=\"1308\" data-end=\"1357\"><strong data-start=\"1312\" data-end=\"1355\">5. Physical Addressing (MAC Addressing)<\/strong><\/h3>\n<ul data-start=\"1358\" data-end=\"1514\">\n<li data-start=\"1358\" data-end=\"1439\">Assigns a <strong data-start=\"1370\" data-end=\"1408\">MAC (Media Access Control) address<\/strong> to each device in a network.<\/li>\n<li data-start=\"1440\" data-end=\"1514\">MAC addresses are <strong data-start=\"1460\" data-end=\"1482\">unique identifiers<\/strong> for devices in a local network.<\/li>\n<\/ul>\n<h3 data-start=\"1516\" data-end=\"1566\"><strong data-start=\"1520\" data-end=\"1564\">6. Reliable Transmission (In Some Cases)<\/strong><\/h3>\n<ul data-start=\"1567\" data-end=\"1718\">\n<li data-start=\"1567\" data-end=\"1718\">Some <strong data-start=\"1574\" data-end=\"1603\">Data Link Layer protocols<\/strong> (like <strong data-start=\"1610\" data-end=\"1643\">PPP &#8211; Point-to-Point Protocol<\/strong>) ensure <strong data-start=\"1652\" data-end=\"1678\">reliable data transfer<\/strong> by <strong data-start=\"1682\" data-end=\"1715\">acknowledging received frames<\/strong>.<\/li>\n<\/ul>\n<h3 data-start=\"1725\" data-end=\"1766\"><strong data-start=\"1728\" data-end=\"1764\">Protocols of the Data Link Layer<\/strong><\/h3>\n<p data-start=\"1767\" data-end=\"2006\">The Data Link Layer consists of two sublayers:<br data-start=\"1813\" data-end=\"1816\" \/><strong data-start=\"1820\" data-end=\"1859\">Logical Link Control (LLC) Sublayer<\/strong> \u2013 Handles <strong data-start=\"1870\" data-end=\"1905\">error checking and flow control<\/strong>.<br data-start=\"1906\" data-end=\"1909\" \/><strong data-start=\"1913\" data-end=\"1952\">Media Access Control (MAC) Sublayer<\/strong> \u2013 Manages <strong data-start=\"1963\" data-end=\"2003\">device addressing and access control<\/strong>.<\/p>\n<h3 data-start=\"2008\" data-end=\"2048\"><strong data-start=\"2012\" data-end=\"2048\">Common Data Link Layer Protocols<\/strong><\/h3>\n<table data-start=\"2049\" data-end=\"2704\">\n<thead data-start=\"2049\" data-end=\"2083\">\n<tr data-start=\"2049\" data-end=\"2083\">\n<th data-start=\"2049\" data-end=\"2064\"><strong data-start=\"2051\" data-end=\"2063\">Protocol<\/strong><\/th>\n<th data-start=\"2064\" data-end=\"2083\"><strong data-start=\"2066\" data-end=\"2081\">Description<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody data-start=\"2117\" data-end=\"2704\">\n<tr data-start=\"2117\" data-end=\"2210\">\n<td><strong data-start=\"2119\" data-end=\"2144\">Ethernet (IEEE 802.3)<\/strong><\/td>\n<td>Wired LAN protocol, uses <strong data-start=\"2172\" data-end=\"2183\">CSMA\/CD<\/strong> for collision detection.<\/td>\n<\/tr>\n<tr data-start=\"2211\" data-end=\"2305\">\n<td><strong data-start=\"2213\" data-end=\"2236\">Wi-Fi (IEEE 802.11)<\/strong><\/td>\n<td>Wireless LAN protocol, uses <strong data-start=\"2267\" data-end=\"2278\">CSMA\/CA<\/strong> for avoiding collisions.<\/td>\n<\/tr>\n<tr data-start=\"2306\" data-end=\"2427\">\n<td><strong data-start=\"2308\" data-end=\"2341\">PPP (Point-to-Point Protocol)<\/strong><\/td>\n<td>Used in <strong data-start=\"2352\" data-end=\"2363\">dial-up<\/strong> and <strong data-start=\"2368\" data-end=\"2375\">DSL<\/strong> connections for <strong data-start=\"2392\" data-end=\"2424\">point-to-point communication<\/strong>.<\/td>\n<\/tr>\n<tr data-start=\"2428\" data-end=\"2529\">\n<td><strong data-start=\"2430\" data-end=\"2469\">HDLC (High-Level Data Link Control)<\/strong><\/td>\n<td>Used in WAN networks for <strong data-start=\"2497\" data-end=\"2526\">synchronous communication<\/strong>.<\/td>\n<\/tr>\n<tr data-start=\"2530\" data-end=\"2598\">\n<td><strong data-start=\"2532\" data-end=\"2547\">Frame Relay<\/strong><\/td>\n<td>Used in <strong data-start=\"2558\" data-end=\"2577\">high-speed WANs<\/strong>, replaced by MPLS.<\/td>\n<\/tr>\n<tr data-start=\"2599\" data-end=\"2704\">\n<td><strong data-start=\"2601\" data-end=\"2637\">ATM (Asynchronous Transfer Mode)<\/strong><\/td>\n<td>Used in telecommunication networks for voice, video, and data.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3 data-start=\"2711\" data-end=\"2726\"><strong data-start=\"2715\" data-end=\"2726\">Summary<\/strong><\/h3>\n<p data-start=\"2727\" data-end=\"2994\"><strong data-start=\"2729\" data-end=\"2752\">The Data Link Layer<\/strong> provides <strong data-start=\"2762\" data-end=\"2776\">error-free<\/strong> and <strong data-start=\"2781\" data-end=\"2808\">efficient data transfer<\/strong> between directly connected devices.<br data-start=\"2844\" data-end=\"2847\" \/><strong data-start=\"2849\" data-end=\"2927\">It manages framing, addressing (MAC), error detection, and access control.<\/strong><br data-start=\"2927\" data-end=\"2930\" \/><strong data-start=\"2932\" data-end=\"2992\">Common protocols include Ethernet, Wi-Fi, PPP, and HDLC.<\/strong><\/p>\n<p data-start=\"2996\" data-end=\"3073\" data-is-last-node=\"\" data-is-only-node=\"\">Would you like <strong data-start=\"3011\" data-end=\"3032\">detailed examples<\/strong> or <strong data-start=\"3036\" data-end=\"3069\">comparisons between protocols<\/strong>?<\/p>\n<h3 data-start=\"2996\" data-end=\"3073\"><a href=\"https:\/\/www.rlacollege.edu.in\/pdf\/computer\/Computer%20Network%20The%20Data%20Link%20Layer.pdf\" target=\"_blank\" rel=\"noopener\">Computer network Layers &#8211; Data link layer &#8211; what is a function of the data link layer and protocols<\/a><\/h3>\n<div class=\"MjjYud\">\n<div class=\"g Ww4FFb vt6azd tF2Cxc asEBEc\" lang=\"en\" data-hveid=\"CBgQAA\" data-ved=\"2ahUKEwjS5KDsmoGMAxX6bvUHHWZnO0IQFSgAegQIGBAA\">\n<div class=\"N54PNb BToiNc\" data-snc=\"apJHLc\">\n<div class=\"kb0PBd A9Y9g jGGQ5e\" data-snf=\"x5WNvb\" data-snhf=\"0\">\n<div class=\"yuRUbf\">\n<div class=\"b8lM7\">\n<div class=\"dG2XIf XzTjhb\">\n<div class=\"c2xzTb\">\n<div>\n<div>\n<div class=\"xpdopen\">\n<div class=\"ifM9O\">\n<div>\n<div>\n<div class=\"yp1CPe wDYxhc NFQFxe viOShc LKPcQc\" lang=\"en-IN\" data-md=\"471\">\n<div class=\"V3FYCf\">\n<div class=\"g\">\n<div lang=\"en\" data-hveid=\"CBcQAA\" data-ved=\"2ahUKEwjS5KDsmoGMAxX6bvUHHWZnO0IQFSgAegQIFxAA\">\n<div class=\"tF2Cxc\">\n<div class=\"yuRUbf\">\n<div class=\"b8lM7\">\n<h3 class=\"LC20lb MBeuO DKV0Md\"><a href=\"https:\/\/egyankosh.ac.in\/bitstream\/123456789\/86309\/1\/Block-2.pdf\" target=\"_blank\" rel=\"noopener\">UNIT 1 DATA LINK LAYER FUNDAMENTALS &#8211; eGyanKosh<\/a><\/h3>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<p>Here is a complete and simple explanation of:<\/p>\n<hr \/>\n<h1>\ud83c\udf10 <strong>Computer Network Layers \u2013 Data Link Layer<\/strong><\/h1>\n<h2>\ud83d\udcd8 Functions and Protocols of the <strong>Data Link Layer (Layer 2)<\/strong><\/h2>\n<hr \/>\n<h2>\ud83e\udde0 <strong>What is the Data Link Layer?<\/strong><\/h2>\n<blockquote><p>The <strong>Data Link Layer<\/strong> is the <strong>2nd layer<\/strong> in the <strong>OSI Model<\/strong> (Open Systems Interconnection Model).<\/p><\/blockquote>\n<p>\ud83d\udce6 It is responsible for <strong>node-to-node data transfer<\/strong>, <strong>error detection<\/strong>, and <strong>framing<\/strong> the data from the <strong>Network Layer<\/strong> into smaller pieces called <strong>frames<\/strong>.<\/p>\n<hr \/>\n<h2>\ud83d\udd39 <strong>Main Functions of the Data Link Layer<\/strong><\/h2>\n<table>\n<thead>\n<tr>\n<th>Function<\/th>\n<th>Description<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>1\ufe0f\u20e3 <strong>Framing<\/strong><\/td>\n<td>Divides data from Network Layer into <strong>frames<\/strong> (manageable pieces of data)<\/td>\n<\/tr>\n<tr>\n<td>2\ufe0f\u20e3 <strong>Addressing<\/strong><\/td>\n<td>Uses <strong>MAC addresses<\/strong> (physical addresses) to identify devices on the same network<\/td>\n<\/tr>\n<tr>\n<td>3\ufe0f\u20e3 <strong>Error Detection<\/strong><\/td>\n<td>Detects errors using <strong>CRC (Cyclic Redundancy Check)<\/strong> or <strong>Parity Bits<\/strong><\/td>\n<\/tr>\n<tr>\n<td>4\ufe0f\u20e3 <strong>Flow Control<\/strong><\/td>\n<td>Ensures sender doesn\u2019t overwhelm receiver with too much data<\/td>\n<\/tr>\n<tr>\n<td>5\ufe0f\u20e3 <strong>Access Control<\/strong><\/td>\n<td>Determines <strong>which device gets access<\/strong> to the shared medium (LAN, wireless, etc.)<\/td>\n<\/tr>\n<tr>\n<td>6\ufe0f\u20e3 <strong>Acknowledgment<\/strong><\/td>\n<td>Confirms that data was received (in protocols like HDLC or PPP)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h2>\ud83d\udd04 <strong>Working in Two Sublayers<\/strong><\/h2>\n<table>\n<thead>\n<tr>\n<th>Sublayer<\/th>\n<th>Function<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>LLC<\/strong> (Logical Link Control)<\/td>\n<td>Error checking, flow control, interface with network layer<\/td>\n<\/tr>\n<tr>\n<td><strong>MAC<\/strong> (Media Access Control)<\/td>\n<td>Controls how devices use the physical medium (Ethernet, Wi-Fi, etc.)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h2>\ud83e\uddea <strong>Popular Protocols at the Data Link Layer<\/strong><\/h2>\n<table>\n<thead>\n<tr>\n<th>Protocol<\/th>\n<th>Description<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\ud83d\udd0c <strong>Ethernet (IEEE 802.3)<\/strong><\/td>\n<td>Most common wired LAN protocol<\/td>\n<\/tr>\n<tr>\n<td>\ud83d\udcf6 <strong>Wi-Fi (IEEE 802.11)<\/strong><\/td>\n<td>Wireless LAN standard<\/td>\n<\/tr>\n<tr>\n<td>\ud83d\udee1 <strong>PPP (Point-to-Point Protocol)<\/strong><\/td>\n<td>Used in direct connections (modems, serial links)<\/td>\n<\/tr>\n<tr>\n<td>\ud83d\udd01 <strong>HDLC (High-Level Data Link Control)<\/strong><\/td>\n<td>Used in WANs for synchronous communication<\/td>\n<\/tr>\n<tr>\n<td>\ud83d\udd27 <strong>ARP (Address Resolution Protocol)<\/strong><\/td>\n<td>Resolves IP address to MAC address (often considered between layer 2 &amp; 3)<\/td>\n<\/tr>\n<tr>\n<td>\ud83d\udef0 <strong>Frame Relay<\/strong><\/td>\n<td>Older WAN protocol using virtual circuits<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h2>\ud83e\uddf0 <strong>Example: How It Works<\/strong><\/h2>\n<ol>\n<li><strong>Data<\/strong> comes from <strong>Network Layer (IP packets)<\/strong><\/li>\n<li>Data Link Layer <strong>adds headers\/trailers<\/strong> \u2192 becomes <strong>frames<\/strong><\/li>\n<li>Uses MAC address to send frame to the <strong>next node<\/strong><\/li>\n<li>Performs <strong>error checking<\/strong> before sending it to Physical Layer<\/li>\n<\/ol>\n<hr \/>\n<h2>\ud83c\udfaf Summary Table<\/h2>\n<table>\n<thead>\n<tr>\n<th>Feature<\/th>\n<th>Description<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Layer<\/td>\n<td>2nd (OSI Model)<\/td>\n<\/tr>\n<tr>\n<td>Unit of Data<\/td>\n<td>Frame<\/td>\n<\/tr>\n<tr>\n<td>Addressing<\/td>\n<td>MAC Address<\/td>\n<\/tr>\n<tr>\n<td>Responsible for<\/td>\n<td>Framing, error detection, access control<\/td>\n<\/tr>\n<tr>\n<td>Common Protocols<\/td>\n<td>Ethernet, PPP, Wi-Fi, HDLC<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h2>\u2753 Would You Like:<\/h2>\n<ul>\n<li>\ud83d\udcc4 A PDF with layer-wise notes (including Physical &amp; Network layer)?<\/li>\n<li>\ud83d\uddbc\ufe0f A visual diagram of OSI model + Data Link Layer?<\/li>\n<li>\ud83c\udfa5 Hindi\/English video lecture?<\/li>\n<\/ul>\n<p>Let me know and I\u2019ll prepare it for you!<\/p>\n<h3><a href=\"https:\/\/www.gpcet.ac.in\/wp-content\/uploads\/2018\/08\/UNIT-I-II-III-CN-R13-JNTUAnew-51-74.pdf\" target=\"_blank\" rel=\"noopener\">Computer network Layers &#8211; Data link layer &#8211; what is a function of the data link layer and protocols<\/a><\/h3>\n","protected":false},"excerpt":{"rendered":"<p>Computer network Layers &#8211; Data link layer &#8211; what is a function of the data link layer and protocols [fvplayer id=&#8221;140&#8243;] Computer Network Layers &#8211; Data Link Layer The Data Link Layer (DLL) is the 2nd layer in the OSI (Open Systems Interconnection) model. It is responsible for reliable data transfer over a physical link [&hellip;]<\/p>\n","protected":false},"author":71,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[98],"tags":[],"class_list":["post-2842","post","type-post","status-publish","format-standard","hentry","category-computer-network"],"_links":{"self":[{"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/posts\/2842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/users\/71"}],"replies":[{"embeddable":true,"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/comments?post=2842"}],"version-history":[{"count":0,"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/posts\/2842\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/media?parent=2842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/categories?post=2842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.reilsolar.com\/pdf\/wp-json\/wp\/v2\/tags?post=2842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}